Cargo may be transported to its destination using one or more of several different types of vehicles, including, for example, ships, trains, aircraft, and trucks. Such cargo is transported while located in the interior of cargo areas. In some cases, cargo may include hazardous, easily flammable, and/or easily combustible materials that may render transport dangerous to the cargo itself, as well as to the vehicle transporting the cargo and operators of the vehicle.
In many instances, cargo may be carried in an area separated from an operator controlling the vehicle. As a result, an operator may be unaware of a fire or explosion that has occurred within a cargo container or within the cargo area. Moreover, due to the nature of a cargo vehicle, there may be a limited supply of fire suppressant available. For example, aboard a cargo aircraft, the weight of any fire suppressant may limit the amount of fire suppressant that may be carried for suppressing fires. Therefore, it may be desirable to limit the amount of fire suppressant used to extinguish a fire in order to reduce the weight carried by the aircraft by focusing any release of fire suppressant on the particular area in need of fire suppressant, rather than merely releasing a large enough amount of suppressant to flood the entire cargo area. Furthermore, the fire suppressant itself may be harmful to some types of cargo. Therefore, it may be desirable to limit the release of fire suppressant to the location in need of fire suppression, so as to limit the spoilage of cargo not in need of fire suppressant.
Because cargo areas experiencing a fire may be located remotely from cargo vehicle operators (i.e., the cargo may be located in an unoccupied and/or difficult to access portion of the vehicle), it may be more difficult to provide fire suppressant to an area experiencing a fire in a timely manner. Therefore, it may be desirable to provide a system for supplying fire suppressant remotely and in a timely manner.
One example of a cargo vehicle having an operator located relatively remotely from the cargo area is an aircraft. The majority of cargo carried by modern aircraft is transported in cargo containers or on cargo pallets. The containers are generally referred to generically as Unit Load Devices (“ULDs”). For safety considerations, ULDs must often be configured to engage an aircraft cargo locking system in order to restrain the cargo containers under various flight, ground load, and/or emergency conditions. Under federal air regulations, ULDs are considered aircraft appliances, are Federal Aviation Administration (FAA)-certified for a specific type of aircraft, and are typically manufactured to specifications contained in National Aerospace Standard (NAS) 3610.
In the cargo aircraft example, while some cargo areas may be conventionally equipped with fire extinguishing bottles intended for manual operation, few cargo containers may be accessible to flight crews during a flight, thereby possibly rendering it difficult to manually extinguish a fire located in an aircraft cargo area using fire extinguishing bottles. In addition, fires may occur inside cargo containers, and if those fires are not suppressed or extinguished, they may breach the walls of the container and spread throughout the cargo area. However, it may be difficult, if not impossible, to suppress or extinguish a fire inside a container without discharging fire suppressant into the interior of the container.
Thus, it may be desirable to provide a system for suppressing a fire associated with a container for which a fire has been detected. In addition, it may be desirable to provide a system for supplying fire suppressant inside the container. Further, it may be desirable to provide a system for supplying a fire suppressant inside the container for an extended period of time or duration of time, for example, so that a cargo aircraft may safely land before a fire spreads throughout the cargo area.
Such a fire suppression system or plurality of systems may be located either in one area of a cargo area, such as a “high risk” area containing particularly hazardous materials, or throughout the cargo area.
Problems associated with detecting and/or suppressing fires are not limited to the cargo transportation industry. Similar problems may arise, for example, wherever cargo and/or other articles are stored in a location that is remote from a person supervising the cargo or other articles, such as in a storage facility. Thus, in a broad variety of situations, it may be desirable to remotely detect and/or remotely suppress a fire.
In many applications, it may be impractical or inefficient to store a fire suppression system directly in a container such as a ULD. For instance, containers may be subjected to harsh environments, including extreme cold and heat, shock, vibration, and general abuse. As a result, providing a fire suppression system in each individual container may be impractical due, for example, to accelerated degradation or failure of such systems over time. Moreover, a given company in the cargo freight industry may use thousands of containers, and the cost of equipping each container with a fire suppression system may be prohibitive. Installing, maintaining, and removing the fire suppression system of each container could also be impractical and uneconomical. As a result, there are many possible drawbacks to providing fire suppressing systems in a large number of containers.
In addition, existing technologies and techniques may only provide a limited fire suppressing window. For example, some methods may be a one-time solution, such as devices that supply a fire suppressing agent into a container during a single application. When a fire suppressing agent leaks out of or disperses from a ULD after introduction into the ULD, the fire may grow again and breach the ULD, potentially spreading to surrounding cargo. This may severely limit the time available for a flight crew to safely land a cargo aircraft, for example. Some tests have shown that a single application of fire suppressing agent into a container may be effective for twenty minutes or less. This may be inadequate, for example, for a cargo aircraft during a transoceanic flight, where it may take several hours to fly to the closest airport suitable for landing. Therefore, it may be desirable to provide a consistent or repeated supply of fire suppressing agent to a container over an extended duration.